Just found out about this site. It's amazing and I hope I can contribute and learn together with everyone.

I have a query regarding the LO temperature and bearing vibration. Is there any correlation between these 2 parameters? Previously in my plant we were operating our ST with LO temperature around 48-50 deg C and everything was fine. However, after a recent outage it changed whereby when the LO temperature increases, the bearing vibration increases too (bearing 2x). We are quite puzzled as this never happened before.

Is it suppose to be this way and we never knew it or is something wrong?

Good that this gentleman raised this query, I am working for DCS implementation company, presently we are replacing Existing DCS with our New DCS, hence we need to follow exactly similar to configuration in the new DCS.

While we are doing our implementation, we found that in the Vibration Trip multiple configuration, Bearing temperature alarm, is also consider in the vibration trip multiplier.

We also puzzled why this is consider in trip bypass, generally vibration trip multiply is applied during start up and it is removed after defined time.

It means there is a relation between bearing temperature alarm and vibration.

Dear CTTech,you are right. What I meant by ST is Steam Turbine. But my concern is the relationship between the lube oil temperature and bearing vibration (bearing 2x particularly). Does it has something to do with the viscosity of the lube oil,whereby if the temperature of the lube oil increases it will reduce the viscosity and therefore causing higher vibration? Well,this is the only explanation I can think of.

But one more thing that is confusing me is that,we used to run our ST with the lube oil temperature around 48-50 deg C as I have mentioned earlier in my query without any effect to the bearing vibration. This phenomena has just started after a recent outage whereby if the lube oil temperature reaches about 49-50 deg C,the bearing vibration also picks up.

1. Yes we are using proximity type vibration sensors and we have carefully gapped them.

2. No seals were changed.

3. Seal steam pressure remains.

4. After the sudden tripping of ST, our rotor experienced bow. Thus, we had to remachine it. However, we can't do much on the HP side, therefore we had to add balance shot at the HP plates to compensate for that.

Sorry for the unclear statement Phil. What I meant by "Bearing 2x" is vibration on bearing number 2, "x" axis. It shows significant increase in vibration when the lube oil temperature increases. Other bearings vibration increases too, but the increase is not very significant.

as a matter of fact, the high temperature of the lube oil in your case is not a "reason" for vibration , it's only a "result".

there are too many reasons to get a high lube oil temperature,one of them is "friction" which causes a lot of heat and as a result will bring up lube oil temperature which is used as coolant and lubricant simultaneously.

so you have to look for the malfunction in ST shaft, mech. seal, bearings.....etc

Check if you changed the OIL PUMP (attached to the turbine axis) during your last shut down. If you put a new pump, it will have less leaks and pump more oil. As the heat exchanger is the same, this will increase temperature after heat exchanger and thus decrease pressure and viscosity.

Is there any provision of measuring bearing temperature? I have seen that with rise in vibration the bearing temperature will also rise dramatically. It may very well be that because of rise in bearing temperature the oil can no longer remove the heat from an excessive heated bearing and as a result it's own temperature is increasing.

Vibration is the cause and the temperature is just the effect. Your re-machining also points to this conclusion also.

Users of this site are benefiting from open source technologies,
including Linux,
PHP,
MySQL and
Apache. Be happy.
This page served by Yesod4 in the beautiful
Blackstone Valley of Massachusetts, the home of the American Industrial
Revolution.

FortuneIt is only the great men who are truly obscene. If they had not dared
to be obscene, they could never have dared to be great.
-- Havelock Ellis

You have clicked on the "?" button for search help. To search the
site, enter your search terms in the box labeled "search the site"
and hit Enter.

Some tips for better search results...

Precede each search term with a "+", as follows:

+Modbus +TCP

Otherwise, any post with either term will match.

Use double quotes around phrases, as follows:

+"Allen Bradley" +ethernet

Otherwise, posts containing these words in separate locations will match.

To exclude a word, precede it with a "-", as follows:

+Modbus -Plus

This will return only posts containing "Modbus" but NOT containing
"Plus".

Note that common words (and, that, etc.) and words shorter than 2 characters
are automatically excluded from searches.

Your subscription request is being
processed.

You must be a Control.com member
to subscribe to threads. Please log in and try again.

If you're not already a member, consider joining. It's free,
and you can customize the content you view, as well as being
able to subscribe to threads and topics, getting new posts
delivered to your email as they appear.

Username

Password

Remember me on this computer

Select the categories for which you would like to
see messages displayed...

Applications

Application Questions and Problems

Automation Business

The Business of Automation and Control

Communications

Communications systems and equipment.

Engineering

Engineering and workplace issues.

HMI

Human-Machine Interface and SCADA.

Information

Information resources, documentation.

Languages

Programming languages.

Motion Control

Motion control, servos, steppers, etc.

Networking

Local and wide area networking in factory automation.

Open Control

Open interfaces, software and hardware

PCs in Automation

Computers in manufacturing; also hardware discussion.

PLCs

PLCs and related questions.

Power Generation

Power generation equipment control.

Process Control

Continuous process industries, DCS questions.

Sensors

Sensor technologies.

Software in Automation

Software, including programming, OS issues, etc.

You must be a Control.com member
to vote on a post. Please log in and try again.

If you're not already a member, consider joining. It's free,
and you can customize the content you view, as well as being
able to subscribe to threads and topics, getting new posts
delivered to your email as they appear.